Reducing levels of amyloid-B, the peptide that accumulates and causes Alzheimer's disease, is the most likely method to treat or prevent this disease. Our preliminary data demonstrates that postsynaptic signaling mechanisms, mainly through NMDA and orexin receptors, can dramatically reduce AB production and levels. We propose that both of these neurotransmitter systems activate substantially different signaling cascades that eventually converge on the extracellular-regulated kinase (ERK) signaling pathway. Activation of the ERK signaling cascade rapidly and dramatically reduces AB levels in vivo. This proposal will determine the cellular pathways that link these neurotransmitter receptors to ERK and AB metabolism. Understanding these pathways will provide insight into factors that contribute to disease risk as well as provide new pathways that could be targeted for therapeutic inten/enfion to treat AD.